Founders Rule

Of course, many CEOs of today's top tech companies are also the founders. (See: Larry Page, Mark Zuckerberg, Jeff Bezos.) Founders accounted for 69 percent of the current CEOs, according to Russell Reynolds. Meanwhile, about 21 percent were hired externally and nearly 10 percent came from the inside.

The situation is far different for Fortune 100 companies, where 76 percent were promoted internally, 18 percent came from the outside and founders made up 6 percent.